On the wall of Ted Pietsch’s office is a photo of a fish with teeth so big it must have trouble closing its mouth—the sort of fish that piranha have nightmares about. “This one might have the largest teeth in the world, relative to its body,” Pietsch says. When asked if he has mentioned this to the folks at the Guinness Book of World Records, he breaks into a grin. “Hey, that’s a good idea! That could be a third one.” Pietsch, you see, has already cracked the Guinness Book twice—for identifying the smallest sexually mature vertebrate on earth, and for identifying the species with the largest male-to-female size disparity. Both are anglerfishes, the famous ocean-dwellers that “angle” for their prey with bioluminescent bait that grows out of their heads. Pietsch, a UW professor of ichthyology and the curator of fishes for the Burke Museum, is the world’s leading authority on them. Next year he’ll publish the definitive book, Deep Sea Biodiversity: Evolution of Deep Sea Anglerfishes. “I still remember precisely where I was sitting the first time I saw one,” he says. “It was 1967. I was a little naïve kid from the Midwest who had gone out to USC for grad school, and they’d given me a job sorting collections of deep-sea fishes that had just been brought in aboard ships. So I was dumping out these gallon jars, and I saw this crazy-looking fish and just freaked out, and I’ve never stopped looking at them.”